Abstract:
The effects of Nd2O3 and Y2O3 dopants on the phase stability of Ba2Ti9O20 (dibarium nonatitanate oxide, abbreviated “B2T9”) prepared using conventional solid-state methods were investigated. The study examined the effects of these dopants on densification, X-ray diffraction patterns, microstructure development and the microwave dielectric properties of Ba2Ti9O20 ceramics. The results reveal that the dopants facilitated formation of pure Ba2Ti9O20 phase sintered at 1300 °C/3 h, compared to the use of pure host materials. Nd2O3 doped B2T9 displayed improved microwave dielectric properties, including dielectric constant as high as 39, quality factor in the range 12,057–13,299 at 7 GHz and temperature coefficient frequency of 12–17 ppm/°C. Y2O3 doped B2T9 had dielectric constants with values up to 37, quality factors = 7,248–10,413 at 7 GHz and temperature coefficient frequencies = 9–13 ppm/°C. The enhanced dielectric
properties of the Nd2O3-doped material may be attributed to its denser
microstructure and formation of predominant B2T9 phase with a small
amount of BaO·Nd2O3·5TiO3.